1. Field of the Invention
The present invention pertains to communications systems and more particularly to methods for forming a message that includes a subaddress and for routing the message from a source terminal through a network destination server and to a destination terminal.
2. Discussion of the Background
Although facsimile machines have found a niche in the evolving field of computer and Radio Frequency (RF) communication networks, problems exist in "integrating" these paper-based legacy systems into modern communications networks. While advances have been made in the facsimile technology community that permit facsimiles to route messages within networks to particular destination terminals, each known option is cumbersome in that each option requires an operator to input long code words into a source facsimile machine.
The basic function of a facsimile machine is to scan and convert graphics material into digital signals and then transmit the digital signals, either locally or remotely, to another device that produces in record form a likeness of the subject graphics material. Most often, facsimiles are used to convert textual information from a hard-copy document into discrete electrical analog pulses which are transmitted over an analog telephone line to a destination facsimile, where the image is then reproduced.
Traditionally, two facsimile machines (source and destination) communicate through a direct-dialed telephone connection. The source facsimile initiates the connection between the two facsimile machines by dialing a telephone number of the destination facsimile. The connection is made when the telephone line rings at the destination facsimile location and the destination facsimile picks-up the line. The two facsimiles then exchange some "handshaking" information, after which the facsimile image is transmitted to the destination terminal. Included in the handshaking information is a terminal station identifier (TSI) field, which is used to announce to the destination facsimile machine the identity of the source facsimile machine.
Limitations with the above-described traditional approach are that it requires users at the destination and source terminals to manually interact with their respective facsimile machines, and requires a dedicated telephone line to service the destination facsimile machine. Clearly, dedicated lines and manual interaction are not desirable attributes for "integrating" facsimile machines into modern communications networks. The present inventor has determined that a need exists for facsimile machines to communicate to other terminals using the shared resources of a network, and to have a "user-friendly" user interface that makes it easy for a user to send messages to destination terminals connected to data networks.
Newer data network architectures solve part of the above-mentioned problems by connecting destination terminals to a destination server. These architectures allow multiple destination terminals to share a selected few telephone lines. The architectures include a source terminal connected to the destination server through a public switched telephone network (PSTN) line, which a user accesses by first dialing the telephone number of the destination server. Once the telephone number is dialed, the facsimile can provide to the destination server a facsimile message in digital format which the server may then route to network terminals (facsimile machines, computers with and without facsimile cards, or data communication networks that can receive image based information). The destination server does, however, require prior knowledge of a particular routing address in order to route a message to a corresponding destination terminal.
"Intelligent" servers acquire the destination terminal address by using software capable of extracting a routing address from an incoming facsimile message. Advances in facsimile machines, facsimile message protocols, and intelligent servers permit "subaddresses" (i.e., the routing address) to be included as part of the facsimile message formed at a source facsimile terminal. One example of an advancement in the subaddressing field is U.S. Pat. No. 5,206,743, which discloses a methodology for including a subaddress in the Transmit Station Identifier (TSI) field of a facsimile message. The subaddress, as well as other information, is inserted by the operator at the source facsimile.
A limitation with the above-described subaddress methodology is that it requires the operator to enter a lengthy code word. The lengthy code word is both difficult for the user to remember and too long to be displayed on some facsimile machine displays. In particular, the operator inputs a consecutive string of characters including a destination telephone number, a five digit subaddress suffix and unique control characters (i.e., "#" and "*" characters) appropriately spaced in the code word to distinguish the subaddress from other fields in the message. This method is awkward in that a user has to remember a long string of characters that form the code word, and remember precisely where in the code word to insert the control characters. Furthermore, if the capacity of the facsimile's display is less than the length of the code word, a portion of the code word will scroll off of the display, thereby forcing the user to enter the remainder of the code word without the benefit of seeing the full string of characters already entered by the user.
NOVELL, Inc. offers for sale NetWare.RTM. version 4.1, as described in the document NEST Autoroute Code Definition, .COPYRGT.1995 Novell, Inc., part number 106-000644-001, the substance of which is incorporated herein by reference. NetWare.RTM. version 4.1 is a software product hosted on a destination server that permits an incoming facsimile message to be routed to a destination terminal as long as the incoming message is formatted in the NEST autoroute.COPYRGT. code. The NEST autoroute.COPYRGT. code requires the source terminal to produce a consecutive string of characters forming a code word, like that described above in reference to U.S. Pat. No. 5,206,743. The code word includes the subaddress, the destination telephone number, and unique characters used to separate the subaddress. The destination server changes the subaddress into an "identification number" that is unique to the destination terminal. The "identification number" is not a universal address (such as an Internet Protocol (IP) address or an asynchronous transfer mode (ATM) address). While, facsimile machines conforming to the CCITT G3 (Comite Consultatif Internationale de Telegraphique et Teleponeque Group 3) format are compatible with NetWare.RTM. version 4.1, the operator of the source facsimile is inconvenienced by having to remember the code word.
The NOVELL NetWare.RTM. software also provides a "polling" feature that provides a source terminal with remote access to files located on a destination terminal. A limitation with this polling approach is that it does not provide a means by which a remote facsimile terminal can conveniently input a polling instruction.